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I deal with a lot of remote offices located in parts of the world where the local grid power supply is unreliable.

  • Power can go off anytime with no warning, with outages ranging from minutes to days
  • Power fluctuation is wild, with spikes and brown outs

Currently the offices will have some or all of the following:

  • A generator, with an inverter, or some sort of manual switch
  • A big UPS or battery array connecting a number of devices
  • Several smaller APC UPS with computers attached
  • Low cost Voltage Regulators sometimes connected between mains and UPS or device.

I know that each of these things needs to be appropriately rated for the equipment to which it is connected (although I am not sure how to calculate the correct rating).

The offices will generally have the following equipment (in varying quantities):

  • some sort of internet connection device (VSAT router, ADSL modem, WiMax router)
  • Cisco ASA 5505 firewall
  • a bunch of PCs
  • printers
  • one server

I don't seek to replace the advice of an electrician, but in some of these locations they only answer the questions you ask them, so I need to make sure I have enough understanding of the essentials to protect equipment from damage, and possibly get through some power cuts.

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It isn't clear what you are asking for here. The only considerations I can see here are 1) do you have everything connected to a UPS, and 2) is the generator in working order and sized to handle the load? I'm also not sure if that "stabiliser" line is an attempt at a joke. –  psusi Mar 21 '12 at 15:19
    
Not a joke - but they are called Voltage Regulators, not stabilisers (but they are sometimes called that) - question updated to reflect. –  dunxd Mar 22 '12 at 10:59
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2 Answers

I have a client in the desert outside of Palm Beach, California... Worst power ever! They have the spikes, dips and brownouts/blackouts you mention. In 7 years working with them, I've blown 10 HP ProLiant power supplies, numerous power strips, multiple UPS units and batteries and a handful of network switches. I don't think there's much you can do to stabilize things. The power cycles will strain your UPS batteries. On the server side, I have a secondary system onsite that can handle application-level failover. I was lucky enough to have an electrical engineer nearby to actually fix components when manufacturer spares weren't available!

Work with the local utility to see if there's anything that can be done. Look at power conditioners. Maybe an online UPS would be helpful to protect equipment, but that comes at considerable cost usually not allocated to branch offices...

Keep cold-spares. Spare network switches are cheap... Spare ASA firewall is inexpensive. Keep a computer or two ready if something blows up.

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Wow - I work with locations like Democratic Republic of Congo and South Sudan. I'd never have imagined you would see this sort of thing in California. We send spare ASA power supplies - those tend to blow first - but not always :-( –  dunxd Mar 21 '12 at 16:03
    
Rural California... desert... poor area. But yeah, you're talking about a pretty harsh environment. –  ewwhite Mar 21 '12 at 16:06
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If possible, it's best to have all electronic equipment behind a UPS + Surge protector. However, more realistically you should protect anything that has a hard drive first. If a device loses power while it's writing to disk, this can impose severe damage sometimes to the point of no repair. Most networking equipment like your router/switches and printers can normally take quite a few power beatings, as they use RAM-style disks when they are running. Surge protection is almost necessary for all devices in situations of spiky power.

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